The LP53K - the K meaning "kurz" or short.
The pic below shows the relationship in size between a standard LP53, and the LP53K.

This is actually a "contrived rarity" that was the result of my having two brutalized LP53 "parts guns", and my being bored during a long, cold winter a few years back. The actual rifled portion of the barrel, and the factory crown were un-touched by the "surgery" - only the counterbored section of the muzzle has been removed, so there have been no ill effects to the velocity, nor accuracy of the gun. It is just a wee bit more difficult to cock, but I knew that would be the case at the outset of the project.

I'm afraid I've just performed the cardinal sin and chopped my excellent condition lp53 down like Lens..
I must say a special thankyou to Len for his advice. I'm an engineer myself but nothing like first hand experience of the job, especially as Len had done such a superb job....
I must admit to huge and terrible stress on the first stroke of the hacksaw just behind the rear sight and needed a shot of brandy after I had took it off......but all good..
I span the barrel between centres and achieved similar results to Len...
Drilling off the rear sight intact a much more difficult task than Len owing to having no barrel length to hold as Len used 2 barrels....but milled it off..
I'll get it refinished and put the results up....
I know many will be unhappy that I performed my mod on a good version while Len is spared this criticism owing to a duffer ....but hey ho ....u only live once...
It's magnificent ..
thanks Len

Cheers buddy who knows mate we may become part of an illustrious club ....
The evolution of the lp53
I don't know why but I'm getting more out of it.
This on paper should not be the case due to the shorter sight base potentially reducing accuracy but I think the reason is I'm handling the recoil better ....that's my initial feelings only.....you are better placed to support such a judgement ..

I have seen a few shortened LP53 pistols over the years, but they were not done particularly well, and it was clearly obvious what had been done.
That is why I took great care to try to make mine look like it came from the factory with the short barrel.

I didn't really notice any practical difference at all in either velocity nor accuracy.
After all, the only thing that had changed was the sight radius, and by not nearly enough to adversely affect accuracy potential at 10M.